In general, a medical device may include an elongate portion configured to be inserted into a body cavity, and the elongate portion may be coupled with a control portion. The medical device may also include a steering mechanism, which may be adapted to steer a distal tip of the medical device. The steering mechanism may include steering wires disposed lengthwise through lumens in the elongate portion. The steering wires may attach a distal end of the elongate portion to the control portion. In certain instances, a proximal end of a selected steering wire may be tensioned, which may cause deflection of the distal tip of the medical device in a select direction, such as, for example, left-right or up-down.
In some conventional medical devices, two steering wires may be tensioned using a pulley located in the control portion of the medical device. The pulley may include a pulley wheel mounted on a shaft, and the two steering wires may be connected to the circumference of the pulley wheel. Rotation of the shaft may pull one wire in a proximal direction while releasing the other wire, resulting in deflection of the distal tip of the medical device. In certain embodiments, the force required for rotating the pulley may increase as the wire is pulled farther. Such increased force may interfere with smooth and unencumbered steering of the medical device.
Therefore, a need exists for an improved control system for steering the medical device.